Apparatus for stripping web material from nip rolls



Sept. 30, 1969 H. T. ROGERS 3,469,755

APPARATUS FOR STRIPPING WEB MATERIAL FROM NIP ROLLS Filed Sept. 29, 1967 3 Sheets-Sheet 1 Q\ on Q I Sept. 30, 1969 H. T. ROGERS 3,469,

APPARATUS FOR STRIPPING WEB MATERIAL FROM NIP ROLLS Filed Sept. 29. 1967 5 Sheets-Shem i;

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Heady 1'. 120 2246, yflwa W 013802 82966 fig 44025 m W United States Patent @fice 3,469,755 Patented Sept. 30, 1969 U.S. Cl. 226172 2 Claims ABSTRACT OF THE DISCLOSURE An apparatus for preventing web material passing between nip rolls from adhering to the surfaces thereof. The apparatus includes a guide member on the delivery side of each roll, and a plurality of endless belts passing around each nip roll and its associated guide member, the said belts being seated in appropriately spaced grooves in the roll surfaces.

Description of the invention There are a number of situations, particularly in the textile industry, where web material is pulled between two squeeze or nip rolls and thereafter deposited in a substantially tensionless condition in the form of loose overlapping folds. In such situations, there is a tendency for the web material to adhere to one of the rolls immediately after emerging from the nip, thus causing serious wrapups with attendant damage to the material as well as loss of valuable production time. This problem becomes more acute as the speed of the material passing between the rolls increases.

The present invention is directed to a solution of this problem and has as one of its primary objects the provision of means for preventing web material from adhering to the surfaces of nip rolls, regardless of the speed at which the material is being run therebeteween.

Another object of the present invention is to provide means for preventing web material from adhering to the surfaces of nip rolls without in any way detracting from the uniformity of the pressure per unit area to which the material is being subjected.

A further object of the present invention is to effectively strip web material from the surfaces of cooperating nip rolls without marking or otherwise damaging the material.

These and other objects and advantages of the present invention will become more apparent as the description proceeds with the aid of the accompanying drawings, wherein:

FIG. 1 is a side view partially in section of an apparatus embodying the concepts of the present invention;

FIG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a sectional view taken along line 33 of FIG. 2; and,

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3.

Referring initially to FIGS. 1 and 2, there is shown the base member of a machine frame supporting a pair of nip rolls 12 and 14. The lower nip roll 12 is mounted between a pair of conventional anti-friction bearing blocks 16 secured to the base member by means of screws 18. The upper nip roll 14 is similarly supported between hearing blocks 20, the latter being secured in a depending fashion to arm members 22 which are pivotally connected at one end as at 24 to the machine frame. The arm members 22 are interconnected by an intermediate brace 26 to which is removably attached a weight 28-. By changing weight 28 and/or varying the distance between it and pivot point 24, the pressure being exerted at the nip on the material M passing between the rolls can be varied over a wide range to suit current operating conditions.

In the embodiment herein described, lower roll 12 is driven in a counterclockwise direction by means connected to shaft extension 30. The drive means which may be of any conventional design, does not form part of the present invention and has therefore not been illustrated. Driving lower roll 12 in a counterclockwise direction causes the upper roll 14 to rotate as an idler in the opposite direction, with the material M being pulled through the nip from right to left as viewed in FIGS. 1 and 2. The material is in tension prior to passing through the nip, and after leaving the nip, it is allowed to drop on the delivery side of the rolls in a substantially tensionless condition in the form of loose overlapping folds 32.

The means for preventing the web material M from adhering or wrapping around the nip rolls 12 and 14 will now be described with further reference to FIGS. 3 and 4.

A parallel guide member is provided adjacent each nip roll on the delivery side thereof. In the embodiment herein illustrated, the guide members consist of upper and lower idler shafts 34 and 36 rotatably mounted between anti-friction bearing blocks 38. The bearing blocks of upper shaft 34 are attached to pivotal arm members 22, and the bearing blocks for the lower idler shaft 36 are fixedly attached to base member 10.

A plurality of relatively narrow endless belts or pulleys 40a extend around upper idler shaft 34 and upper nip roll 14. Each belt 40a is seated Within an appropriately spaced groove 42 in the surface of nip roll 14. Lower belts 40b similarly extend around lower idler shaft 36 and grooves 44 in the surface of lower nip roll 12. The belts are of course driven in the same direction as the nip rolls around which they extend by frictional contact with the groove surfaces.

Belts 40a and 40b serve as strippers which effectively prevent the web material M from adhering to either roll surface after passing through the nip. This in turns allows the web material to proceed from the nip in a generally horizontal direction until its forward momentum is dissipated, at which point gravity takes eifect and the material simply falls into a pile of relaxed substantially tensionless folds 32 as shown in FIG. 1. In the preferred embodiment herein illustrated (see FIG. 4), the grooves 42 in the upper nip rolls 14 are offset laterally from the grooves 44 in the lower roll. With this staggered arrangement, the grooves in one nip roll will be opposed by the smooth cylindrical surface of the adjacent roll. In addition, the depth and configuration of the grooves 42 and 44 are such that the belts 40a and 40b will be squeezed to completely fill the grooves and present a continuation of the smooth cylindrical roll surface to the web material M as the latter passes through the nip. For example, as shown in FIG. 4, the depth of each groove 42 and 44 is slightly less than the diameter of the belts 40a and 40b. By choosing a compressible belt material such as rubber or plastic, the belts will be slightly flattened at the nip so as to completely fill the grooves in which they are seated. In this manner, the material M will not be marked or scored and will be squeezed evenly as it passes through the nip.

In view of the foregoing, it can now be seen that the present invention offers a number of important advantages. To begin with, relatively narrow belts 40a and 4012 provide a continuous stripping action which effectively obviates any possibility of the web material M adhering or wrapping around either nip roll. This of itself is extremely important, particularly where the web ma terial is being pulled through the nip at relatively high speeds and thereafter allowed to drop in the form of relaxed tensionless folds. In addition, the above-described arrangement of properly sized grooves and compressible belts enables the web material to be evenly squeezed as it passes through the nip, without danger of it being marked or scored.

Having thus described a preferred embodiment of the invention, it should now be apparent that certain changes and modifications can be made without departing from the scope of the invention. For example, the endless belts need not have a circular cross section but can instead be square or rectangular. However, where the belts are not fabricated of a compressible material, they should preferably be of the same cross-sectional size and configuration as the grooves in the nip rolls. Also, the guide members adjacent each nip roll need not be rotatable idler shafts but can if desired be comprised of fixed shafts over which the endless belts will simply slide.

I claim:

1. Apparatus for preventing adherence of web material to the surfaces of nip rolls comprising: spaced grooves in the surfaces of said rolls, the grooves on one roll being oifset laterally from grooves on the other roll;

4 guide members adjacent each said rolls on the delivery side thereof, said guide members extending in parallel relationship to said rolls; and, a plurality of endless belts passing around each said nip rolls and the guide member associated therewith, said belts being seated in the spaced grooves on said rolls.

2. The apparatus as set forth in claim 1 further characterized by said belts being fabricated of a compressible material, the cross-sectional size and configuration of said grooves being such as to be completely filled by the belts when the latter are squeezed in the nip.

References Cited UNITED STATES PATENTS ALLEN N. KNOWLES, Primary Examiner US. Cl. X.R. 226-191 

